Melatonin Supplementation Improves Cognitive Function in Type-2 Diabetes Mellitus: A Quasi-Experimental Study

Introduction Diabetes mellitus is a metabolic disorder characterized by dysregulation and alteration of glucose and lipid metabolism, leading to cognitive impairment. Impaired cognition is caused by a string of risk factors, among which glycemic dysregulation could be a reversible factor. The study aimed to evaluate the effectiveness of melatonin supplementation on impaired cognition in patients with type 2 diabetes mellitus, as assessed by changes in the Montreal Cognitive Assessment (MoCA) score. Method A quasi-experimental design (single-blinded) was conducted with a once-daily tablet of oral melatonin 5 mg at night for three months versus a placebo given in a cohort of 154 patients with type 2 diabetes mellitus after exclusion of a prior major neurological disorder. Patients having a mild to moderate cognitive impairment diagnosed via a validated tool, MoCA, with scores ranging from 10 to 25, were randomly assigned to two treatment groups (melatonin versus placebo). A follow-up at three months was carried out for the cognition scale and biochemical markers (HbA1C, low-density lipoprotein cholesterol (LDL-c), C-reactive protein (CRP), and serum uric acid), and compared with baseline parameters for both groups. Results A total of 154 subjects with a mean (SD) age of 49.98±10.08 years, a mean (SD) HbA1C of 9.49±1.50, and 90 (58.4%) female participants were allocated into two groups, i.e., Melatonin and Placebo. At 12 weeks of treatment, the melatonin-treated group showed improved MoCA score compared with the placebo group, mean (SD) MoCA, 21.35±4.75, OR=1.84, (95%CI, 0.355-3.33); p=0.016. The melatonin group also showed improvements compared to the placebo group with mean (SD) HbA1C, 8.68±1.38, OR=-0.585 (95%CI=-1.01-0.152); p=0.008, mean (SD) LDL-c, 154±34.10, OR= 1.01, (95%CI=-9.88-11.90); p=0.854, and mean (SD) CRP, 5.80±0.39, OR=-0.181 (95%CI=-0.305-0.057); p=0.004. Conclusion Melatonin supplementation in patients with type 2 diabetes mellitus led to significant improvement in cognitive function as assessed by the MoCA score, along with reductions in HbA1C and CRP levels. No significant effects were observed on LDL-c and uric acid. These findings suggest that melatonin may serve as a useful adjunctive therapy for improving cognition and certain metabolic parameters in diabetic patients.